This proposal deals with the role of Chlamydia trachomatis in the immuno-pathogenesis of pelvic inflammatory disease. The approach included the isolation, characterization of the genus and serovar specific antigens. Characterization of the genus antigen will include studies on the structure of this glycolipid and the linkage of the polysaccharide to the lipid. In addition, studies on the biosynthesis of this antigen may be important in the mechanism of infectivity. The serotype antigens have been shown to have enzymatic activity. They are phosphate-esterases which may allow them to play a role in the endocytosis of columnar epithelial cells of the endometrium. Attempts will be made to localize the site of reaction with the cell receptor and follow the infective process. The proposal includes characterizing the reaction of specific antibodies to the purified antigens. Each antibody from serum and secretions of patients will be characterized as to isotype and subclass. The biological activity in terms of neutralization of the serovar enzymatic activity, neutralization of the organism for infectivity in cell culture and for primary cultured columnar epithedial cells from patients with PID will be attempted. The results will be correlated with the disease to determine a possible mechanisms for immunopathology of PID.